This invention relates to automatic suspension control systems for motor vehicles, and more particularly to a computer controlled air suspension system for motor homes and recreational vehicles.
Ride-height control systems for motor homes and recreational vehicles are well known in the art. These systems typically utilize air suspension systems which permit the distance between the axles and chassis to be adjusted according to the amount of pressure within the air bags. The ride-height of the vehicle may therefore be adjusted for varying loading conditions, road conditions, wind, and rough terrain. Systems for maintaining a particular ride-height for varying conditions generally utilize a vehicle pneumatic system, comprised of an air compressor and air tank, and a pneumatic valve connected to each of the vehicle air bags. Each of the valves is secured to the vehicle chassis and connected to the vehicle axle by means of a mechanical linkage. As the distance between the chassis and axle fluctuates, air is supplied to, or vented from, each air bag through its respective valve. These systems are unsatisfactory for a number of reasons. First is the requirement for manually adjusting each valve linkage to select a new ride height as environmental conditions change. Second, these systems utilize a great deal of air, and therefore put a constant drain on the vehicle pneumatic system, due to the constant transfer of air into and out of the bags as the chassis and axle oscillate and the system xe2x80x9chuntsxe2x80x9d for the proper setting. Further, with known systems, adjusting the sensitivity of the system for different quality of ride requires changing the pneumatic valves.
The present invention discloses a vehicle ride-height and automatic suspension control system with selectable ride-heights and sensitivity. The invention also provides for automatic control of the suspension system as the vehicle rounds curves or corners by means of a gear tooth counter and direction sensor that is combined with the vehicle steering system.
The system of the invention utilizes a series of photoelectric cells activated by shutters on a shaft that are placed offset to each other and are mechanically linked between the vehicle chassis and axle. The offset provides for more than one ride-height setting.
Sampling a photoelectric cell by a controller every millisecond increments or decrements a counter or register. When the counter reaches either the upper or lower threshold value the appropriate solenoid valve is energized to inflate or deflate a particular air bag for a duration of time that is selected by the user.
System sensitivity is adjustable by selecting different counter thresholds and by selecting the duration of solenoid actuation.
In addition, a gear tooth counter and direction sensor are utilized to detect direction and degrees of rotation of the steering wheel. This allows the controller to select one of two modes (economy or active) of suspension control. Surpassing set limits of movement of the steering system determines the appropriate selection of modes to minimize roll of the vehicle when rounding curves or corners or when abrupt turns are made.